The electromagnetic spectrum can be viewed as a natural resource that is potentially available for an unlimited number of users and uses. Unfortunately, much of the electromagnetic spectrum lies fallow due to “command-and-control” regulatory policies that impede investments by new entrants and innovative new uses of the spectrum. These regulatory policies are typically not market-driven and are thus not responsive to economic signals and the public interest. As a result, many regulatory policies tend to lock in incumbent users and uses for the spectrum, impeding innovation and efficiency.